While there are many studies of comorbidity in combat veterans with posttraumatic stress disorder (PTSD), studies of PTSD from other sources of trauma (e.g., disasters, crimes, and civil violence) are just beginning to emerge. This is the first formal review comparing patterns of comorbidity in PTSD from different sources of trauma. Specific attention is given to the relative frequencies of substance abuse, depression, generalized anxiety, phobic, panic, somatization, psychotic, and personality disorders. The findings reveal that although similarities exist, the cornorbidity profiles differ according to the type of trauma experienced and the population studied. Additionally, the evidence suggests that the associated psychiatric disorders are not truly comorbid, but are interwoven with the PTSD.